Electrode foil for solid electrolytic capacitor, manufacturing method thereof, and solid electrolytic capacitor

Abstract

The present invention is an aluminum electrode foil used in a solid electrolytic capacitor, and provides an electrode foil for a solid electrolytic capacitor, a manufacturing method of this electrode foil, and a solid electrolytic capacitor using this electrode foil having an improved voltage resistance and heat resistance at the cut-end part without causing a reduction in the effective area of the electrode foil. According to the manufacturing method of the electrode foil for the solid electrolytic capacitor according to the present invention, a porous film 11 having a thickness within the range of from about 5 to about 100 times the thickness of the barrier film 3 is formed on the surface of an electrode foil 10 , on the cut-end part 5 of this electrode foil 10 . In addition, the present invention provides an electrode foil manufactured according to the above described manufacturing method and a solid electrolytic capacitor using this electrode foil.

What is claimed is:  
     
       1. A method for manufacturing an electrode foil for a solid electrolytic capacitor, comprising etching an aluminum foil to roughen the surfaces thereof, subjecting the foil to a forming treatment to form a barrier film as a dielectric layer on each roughened surface; cutting the formed foil into a predetermined size, and subjecting the cut out formed foil to a forming treatment to form a porous film on the cut-end part, the porous film being a porous oxide film and having a thickness in the range of from about 5 to about 100 times the thickness of said barrier film. 
     
     
       2. The method for manufacturing an electrode foil for a solid electrolytic capacitor as claimed in claim  1 , wherein said porous film formed is further subjected to a forming treatment to form a cut-end-barrier in a base layer of the porous film. 
     
     
       3. An electrode foil for a solid electrolytic capacitor, produced by the manufacturing method as claimed in claim  1  or  2 . 
     
     
       4. A solid electrolytic capacitor produced using an electrode foil for a solid electrolytic capacitor as claimed in claim  3 .